Circuit breaker



y 1934- R. ST. 0. SEESE 1,957,734

CIRCUIT BREAKER Filed Aug. 14, 1930 2 Sheets-Sheet l mmww INVENTDR.

y 3, 1934- R ST. (2. SEESE 1,957,734

CIRCUIT BREAKER Filed Aug. 14, 1930 2 Sheets-Sheet 2 IN VENTOR.

Patented May 8, 1934 UNITED STATES PATENT OFFICE 6 Claims.

My invention relates to a circuit breaker for the protection of an electric circuit, provided with certain automatic devices which will open the circuit breaker and thus interrupt the circuit when circuit conditions of predetermined characteristics appear in the circuit thru which the circuit breaker is supplying energy; which will, after a predetermined interval, reclose the circuit; which will repeat such reclosure for a predetermined number of times at the same or other time intervals, and which will, upon the completion of the predetermined number of reclosures, establish a relatively long interval during which the circuit breaker remains open, and at the termination of which relatively long interval the cycle of reclosures will be repeated.

Other objects of my invention will appear in the further and more detailed description which follows.

With the increasing use of electrical energy for domestic and industrial purposes, it becomes more and more important that users of electricity have as nearly uninterrupted service as possible. Line troubles in the circuits supplying such users tend to interfere with the service, and as such troubles are frequently of short duration, it is desirable to provide for any important supply circuit a circuit breaker which will open when circuit trouble appears, and automatically reclose a short time later on the assumption that the trouble has disappeared. Since the issue of Thomson Patent 508,652, it has been common practice to equip a circuit breaker with a device to cause it to open on the occurrence of trouble, a device to reclose it automatically after a predetermined interval, to repeat the reclosures at the same or different intervals if the trouble persists, and finally to lock the circuit breaker in open position after a predetermined number of reclosing operations. With present-day conditions, it is no longer desirable to lock out the circuit breaker after a predetermined number of reclosures. Instead, it is desirable to make a predetermined number of reclosures. at fairly short intervals, say of a few seconds; then, if the trouble persists, to leave the circuit breaker open for a relatively long interval; finally, to repeat the original schedule of reclosures, and to alternate between the long intervals and the schedules of reclosure until the trouble disappears or the circuit breaker is manually brought to an inoperative position, thus making every effort to restore service. Otheradvantages of this method of reclosing the circuit breaker will be emphasized hereinafter.

In the accompanying drawings, which are schematic elevations, Figure 1 represents an automatic reclosing circuit breaker of the type to be described, together with its associated apparatus, the circuit breaker being in closed position and the auxiliary parts at normal; Figure 2 shows the breaker just after having been opened automatically; Figure 3, just before the breaker closes automatically on the first reclosure; Figure t, just after the first reclosure; Figure 5, just after the initial group of reclosures and at the beginning of the relatively long interval; Figure 6, an end View of the disk used for timing purposes; Figure 7, a modification for reversing the timing schedule on the occurrence of unusualh severe circuit conditions.

In Figure 1 a source 1 is connected by supply crcuit 2 thru circuit breaker 3 to a load circuit 4 and load 5. The circuit breaker tends to the open position by gravity and by spring 6, and is held closed as shown by toggle 7, one end of which is connected to lever 8 and the other end to lever 9, the latter communicating with circuit breaker 3 thru suitable bell crank mechanism 10.

Conventions used in these drawings which will make the action more easily followed are: fixed pins about which certain levers turn, denoted by a circle and a partly concealed triangle, as at 35; guide bearings for the longitudinal motion of rods, denoted by rectangles with both diagonals drawn in, as at 36; bearings for the rotation of shafts, denoted by rectangles with the diagonal only, as at 37; stops to limit the motion of levers and the like, by plain rectangles, as at 42, unless otherwise indicated, where not otherwise shown,

bell cranks are considered to turn about fixed pins placed at their respective angles. Cam 17 is fast to a shaft rotated by motor 16; disks 29, 30 and 38 rotate freely on their respective fixed shafts. motor 16, and circuit breaker 3, are all of common and well known construction, and no invention is claimed for any such element per se. All elements are shown in Figure l; in the other figures, only the elements pertinent to the immediate discussion are reproduced.

Since when circuit breaker 3 is in closed position pin 39 connecting toggle 7 to lever B is slightly above a straight line extending thru the centers of pins 40 and t1, the pressure exerted by circuit breaker 3 in attempting to open forces lever 8 up against stop 42. When the circuit breaker opens, the dead weight of broken toggle 7 and lever 8 tend to force lever 8 downward, such movement being prevented by the contact which The relays 11, current transformers 12, P

end 43 of lever 8 makes with disk 29, as in Figure 2.

When an abnormal circuit condition occurs in load circuit 4, causing current flow exceeding a predetermined value, one or both relays 11 set to operate at or above such value and energized from their respective current transformers 12 will close their contacts and energize solenoid 13 from battery 14, thus causing the plunger of the solenoid to rise and break the toggle, thus allowing circuit breaker 3 to open.

When the circuit breaker 3 opens automatically as described in the preceding paragraph, the following changes are correspondingly made in the positions of the various parts: The lower end of lever 9, pulled to the right by the opening of the circuit breaker 3 closes switch 15, thus energizing motor 16 from battery 14, and also pulls on rod 18, moving it to the right, such motion of rod 18 being communicated thru rods 19 and 29 to hell crank 21, thus lifting pawls 22 and 23 out of engagement with disk 38. At the same time, motion of the upper end of lever 9 moves lever 32 thru its connecting rod 33 and causes the withdrawal from the slot in disk 29 of the end 31 of lever 32, making disk 29 free to rotate. When switch closes, motor 16 starts to rotate, thus rotating cam 17 thru suitable connection as a belt and pulleys. The clockwise rotation of cam 17 at each revolution gives an impulse to lever 25, free end of said lever being in the path of said cam, and each such impulse is communicated to rod 26 and thence to pawls 27 and 23, the corresponding motion of said pawls acting to advance disks 29 and 30 respectively, by notches. Disk 30 tends to oppose such advance rotation on account of the pull of spring 34 attached to its hub, while disk 29 oiiers no such opposition.

When advancement of disks 29 and 30, as clescribed above, continues until a slot in disk 29 comes opposite end 43 of lever 8, when, on account of the above mentioned tendency of lever 8 to rotate, end 43 enters the slot and lever 8 retates downward until toggle 7 straighten-s out and limits such downward motion. This position of lever 8 and toggle '7 is shown in Fig. 3.

Disk 29 now being locked against rotation by the entrance of end 43 in one of its slots, the next impulse given to lever by cam 1'7 will not advance disk 29, and since the contact of pawl 2'7 with the now locked disk 29 will not permit a full travel of rod 26, disk is also barred from further advancement for the time being, the impulse from cam 1'7 being stored up in spring 44, ready to advance the disks one notch when end 43 is withdrawn from the slot.

Lever 3 having now moved downward and toggle 7 fallen into the straightened position as described in the preceding paragraph but one, the mechanism is now in position to reclose circuit breaker 3. On the revolution of cam 17 following the downward movement of lever 8 just described, which downward movement has placed lever 8 directly in the path of cam 17, said cam engages the lower side of lever 8 and forces the latter upward into its original position, the pressure thus exerted being communicated thru the now-straightened toggle 'l, to lever 9 and bell crank 10 and finally to circuit breaker 3, which is closed by this action. End 43 of lever 8 is thus withdrawn from the slot in disk 29, and, on account of the energy previously stored in spring 44 by the preceding revolution of cam 17, as described in the preceding paragraph disk 29 immediately advances one notch so that end 43 will not re-enter the slot in disk 29 should circuit breaker fail to remain closed.

It should be noted that when end 43 enters the slot as described, lever 8 will probably fall on cam 17, there being no necessity for an absolute synchronization between the notching action of pawl 27 which brings the slot in disk 29 opposite end 43, and the angular position of cam 1'7. If lever 8 should rest momentarily on cam 17 in this manner, it will complete its downward motion and allow toggle 7 to straighten as soon as cam 1'7 has passed on, so that cam 17 will on its next half revolution engage lever 8 and close circuit breaker 3 as above described.

Figure 4 shows the relative position of the parts essential to the above-directed reclosure of circuit breaker 3, just as cam 17 completes such reclosure.

The advance of disk 39, above described, away from its initial position draws pin 45 away from lever 46, enabling lever 45 to rise by means of the pull spring 47 into the path of cam 17. Lever 46 thus begins to receive impulses from rotating cam 17. At the same time pin 45 moves away from and releases lever 48, which it initially held against the pull of spring 49. This release of lever 48 would allow spring 49 to pull up on rod 29 and place pawls 22 and 23 in contact with disk 38 were it not for the engagement of the lower end of lever 9 with the end of rod 13. Such action of engaging disk 38 with pawls 22 and 23 is therefore, impossible as long as circuit breaker 3 is open; 1. e., as long as the lower end of lever 9 pulls on rod 18. The impulses of lever 46, therefore, cannot advance disk 38 while circuit breaker 3 is open. The purpose of disk 38 and its associated apparatus is described in a later paragraph.

if the abnormal circuit conditions persist, circuit breaker 3 will again open and disks 29 and 30 will advance until the next slot in disk 29 appears opposite end 43, when another reclosure will take place, followed by additional reclosures, depending on the number of slots in the disk, which for the purpose of this discussion are three in number. The notches in disk 30 being so proportioned that it travels somewhat slower than disk 29, it will complete one revolution just after disk 29 has made one revolution corresponding to three reclosures of the circuit breaker. The completion of the revolution of disk 39 brings pin 45 into contact with lever 53, and the resulting motion of the latter is communicated thru rods 54 and 55 and the intermediate bell crank to the tilting weight 56, which suddenly tilts to the right and pulls rod 55 up quickly, so that projecting pins on rod 55 enage pawls 27 and 28, pulling them out of contact with their respective disks, and a similar pin dis-engages pawl 5'7, allowing the weighted end of pawl 57 to pull it into contact with disk 29. Pawl 64 being attached loosely by a pin to rod 55, and having been previously in contact with disk 30 and preventing the disk from returning to its initial position is dis-engaged from disk 30 by the final upward movement of rod 55, and disk 39 is pulled back to its initial position by spring 34. Due to the design of the mechanism imparting motion from the shaft of cam 17 to the pawl 57, and which consists of worm drives 53 and 59, bevel gears 69, push rod 61 and suitable intermediate shafts, pawl 57 is given a motion considerably slower than that of pawl 27, so that disk 29 is now advanced much more slowly than before. The relative position of parts is indicated in Figure 5. The slow advance of disk 29 in this manner continues until one of the projecting pins preceding each slot in the disk, such as that denoted by 62, engages the projecting lever 63 attached to tilting weight 56, which is thus tilted back to the left, throwing into action pawls 27, 28 and 64, and throwing out of action pawl 57. Disks 29 and 30 now rotate at their original speed, and if the abnormal circuit conditions still persist, another group of reclosures similar to the first occurs.

Assuming abnormal circuit conditions of a long-continued or of a permanent nature, therefore, the net result of the above action is a number of reclosures corresponding to one revolution of disk 29, a relatively long interval to the next reclosure, then additional reclosures corresponding to another revolution of disk 29, or until disk 30 has made a second revolution from its initial position, then another long interval, and so on until the abnormal circuit conditions disappear or until the mechanism is brought to rest manually. This action, which really divides the reclosures into similar groups separated by considerable time intervals, is of value in the case of long continuing abnormal circuit conditions, since the probabilities are in favor of the disappearance of such abnormal conditions during one of the long intervals, if at all, thus relieving the circuit breaker of the strain of interrupting heavy currents during the next group of reclosures, and also giving considerable time for the circuit breaker parts to cool, and for accumulated gases formed by the separation of the circuit breaker contacts under heavy current conditions to disperse before the circuit breaker is again subjected to interrupting duty.

If the abnormal circuit conditions disappear after any reclosure, it is desirable to reset the mechanism to its initial position after a short time so that the identical schedule of reclosing operations above described will occur in the same manner when the next abnormal circuit conditions appear. The method of resetting in this manner will next be described.

The closing of switch 15 by the opening of circuit breaker 3 and corresponding movement of lever 9 has already been described. When disk 30 is at normal position, pin presses latch 66 down out of the path of switch 15. When disk 30 is away from normal position, however, pin 65 is pulled to the left, opposite the recessed portion of latch 66, allowing the latter to be pulled up against the switch lever by spring 67. With latch 66 in this position, released, switch 15 having been closed by the opening action of circuit breaker 3, the switch will remain closed regardless of the subsequent movement of the circuit breaker until disk 30 returns to its initial position allowing rod 18 to move to the right, causing pin 65 to depress latch 66 and release switch 15.

If, therefore, circuit breaker 3 remains closed after any reclosure, pawls 22 and 23 being brought into contact with disk 38 as described in a preceding paragraph and pawl 22 receiving impulses from lever 46, motor 16 continuing to rotate cam 17 on account of switch 15 being held closed, disk 38 will advance until it has made a complete clockwise revolution, at which time pin 68 will engage and push lever 69 to the left, this motion being communicated thru rod to push downward on rod 71 against the pull of Spring 72, to dis-engage pawls 28 and 64 from disk 30 which is pulled back to initial position by spring 34. The return of the disk 30 to initial position causes pin 45 to engage lever 48 which not only unlatches switch 15 thru rod 18 and latch 66, bringing motor 16 to rest, but, thru rods 19 and 20, dis-engages pawls 22 and 23 from disk 38, which is pulled back to its initial position by spring 52, allowing pawls 28 and 64 to re-engage disk 30. Thus all elements of the mechanism are returned to their initial position except the timing disk 29, which has no inherent initial position, and which remains locked by lever 32 from the time of the last reclosure.

Figure 6 shows, for the purpose of making the action of the disks more clear, the edge of disk 29, a portion of the edge or face being notched for engagement by the pawls 27 and 57, and the timing slots being located on the other portion of the face, so that they will not interfere with the notches. Disks 30 and 38 having notches only may have the notches across the entire face.

Figure 7 shows a modification of the tripping mechanism, whereby, if the abnormal circuit conditions cause current flow of an unusual intensity, considerably higher than the value required to operate the relays 11, the first reclosure after the circuit breaker has opened on this unusual current flow will be after a long interval, substantially the same as the previously described long interval between groups of reclosures, instead of after a short interval corresponding to the distance between two slots in disk 29 when rotated by pawl 27. Such an arrangement is advantageous in cases where a severe short circuit exists for a fairly short time, and prevents the reclosure of the circuit breaker on such a short circuit, with the attendant possibility of damage to the breaker and of other apparatus in the circuit. In Figure 7, relays 11 and current transformers 12 are the equivalents of those shown in Figure 1. Solenoids 73 are introduced in the secondary circuits of these transformers together with the relays, and these solenoids are adjusted to pick up their plungers at or above current values which it is considered undesirable for the circuit breaker to open at short intervals. On the occurrence of such a heavy current one or both relays ll operate as usual to trip circuit breaker 3; the simultaneous operation of the plungers in solenoids 73, however, pushes rod 74 over into contact with tilting weight 56, and pushes it to the right from what has been previously described as its normal position. Now, by reference to Figure 1, it is seen that movement of weight 56 to the right throws pawls 27 and 28 out of engagement with their respective disks and brings low speed pawl 57 into engagement with disk 29, after which the operation of the mechanism to produce a long interval prior to reclosure is as previously described. The interruption of current due to opening of circuit breaker 3 de-energizes solenoids 73, and spring 75 restores rod 74 to its former position. If the abnormal condition of unusual degree persists, additional long intervals between reclosures will obviously follow.

What I claim as my invention is:

1. In an electric protective system, an electric circuit a circuit breaker in said circuit, means responsive to a predetermined abnormal current in said circuit for effecting the opening of said circuit breaker, reclosing means for said circuit breaker, timing means responsive to the opening of said circuit breaker for actuating said reclosing means a plurality of times at different time intervals, means for effecting a repetition of said reclosures at said different time intervals after a relatively long time interval during which the circuit breaker remains in the open position, and resetting means for resetting said repeating means to its initial position if the said abnormal current disappears.

2. In an electric protective system, an electric circuit, a circuit breaker in said circuit, means responsive to a predetermined abnormal current in said circuit for eliecting the opening of said circuit breaker, reclosing means for the said circuit breaker, timing means responsive to the opening of said circuit breaker for actuating the reclosing means to effect a predetermined number of reclosures at dififerent time intervals, repeating means for effecting a repetition of said predetermined number of reclosures after a relatively long time interval, and resetting means for effecting a return of the repeating means to an initial position if the circuit breaker remains closed for a predetermined time.

3. In an electric protective system, an electric circuit, a circuit breaker in said circuit, means responsive to a predetermined abnormal cur "ent in said circuit for eifecting the opening of said circuit breaker, reclosing means for the said circuit breaker, timing means responsive to the opening of said circuit breaker for actuating the reolosing means to effect a predetermined number of reclosures at different time intervals, repeating cans for effecting a repetition of said predetermined number of reclosures after a relatively long time interval, resetting means for effecting a return of said repeating means to an initial position if the circuit breaker remains closed for a predetermined time, means responsive to abnormal current in the circuit of higher value than the current value necessary for said means to eiiect the opening of circuit breaker, said higher value current responsive means eiiective to delay said predetermined number of reclosures for a predetermined length of time.

i. In an electric protective system, an electric circuit, a circuit breaker in said circuit, means responsive to a predetermined abnormal current in said circuit for effecting the opening of said circuit breaker, reclosing means for said circuit breaker, timing means responsive to the opening of said circuit breaker for actuating said reclosing means a plurality of times at different time intervals, repeating means for eiiecting a repetition of said predetermined number of reclosures after a relatively long time interval, resetting means for effecting a return to its initial position of the repeating means if the circuit breaker remains closed for a predetermined time, and a common driving means for operating said reclosing means, said timing means, said repeating means, and said resetting means in timed relation to each other.

5. In an electric protective system, an electric circuit, a circuit breaker in said circuit, means responsive to a predetermined abnormal current in said circuit for effecting the opening of said circuit breaker, reclosing means for said circuit breaker, timing means responsive to the opening of said circuit breaker for actuating the reclosing means to efiect a predetermined number of reclosures at different time intervals, repeating means for effecting a repetition of said predetermined number of reclosures after a relatively long time interval, resetting means for effecting a return of said repeating means to an initial position if said circuit breaker remains closed for a predetermined time, a common driving means for operating said reclosing means, said timing means, said repeating means and said resetting means in timed relation to each other, and means responsive to an abnormal current in the circuit of higher value than that required to operate said means for efiecting opening of said circuit breaker, said higher value current responsive means effective to delay said predetermined number of reclosures for a predetermined time.

6. In an electric protective system, an electric circuit, a circuit breaker in said circuit for effecting the opening of said circuit breake reclosing means for said circuit breaker, timing means responsive to the opening of said circuit breaker for actuating said reclosing means, said timing means comprising a device effective thru a predetermined path of travel to actuate said reclosing means a plurality of times, means for changing the rate of travel of said timing device after a predetermined number of reclosures, resetting means effective to reset to an initial position said rate-changing means if the circuit breaker remains closed for a predetermined time, means responsive to abnormal current in said circuit to change the rate of travel of said timing means prior to any reclosure of said circuit breaker, and a common driving means for operating said reclosing means, said timing means and said resetting means in timed relation to each other.

ROBERT ST. CLARE SEESE. 

